How to print a graphic on a glass window
To make a proper glass pane:


Use a BW image instead of a transparent one
Use the Mix Shader node
Add some thickness to your glass pane, so it bends light like in reality






Additional notes


It's better to use Principled BSDF if you're going for realism  
I used two materials so it looks better. Glass with white stripes for front face, and pure glass for the rest.